β-1,3-葡聚糖对感染大肠杆菌肉鸡肠道氧化还原状态、菌群状态和免疫功能的影响

试验选择90只1日龄AA肉鸡随机分成3组,分别饲养于隔离器中。处理1和2饲喂基础日粮,处理3饲喂添加葡聚糖的试验日粮。处理2和3在8、9和10日龄连续口服感染大肠杆菌O780.5mL(浓度为1×1010cfu/mL)。处理1组鸡在8、9和10日龄口腔接种等剂量的灭菌PBS。结果表明,大肠杆菌O78感染会显著降低鸡生长速度(P<0.05),提高死亡率,使感染初期小肠氧化损伤,显著降低肠道乳酸菌数和肠道sIgA量(P<0.05),但显著提高感染初期血清特异性IgG和感染后期空肠sIgA和血清特异性IgG水平(P<0.05)。而日粮添加葡聚糖降低肉鸡死亡率,缓解因感染引起的生长速度降低,减轻肠道氧化损伤,增强肠黏膜抗氧化能力,显著提高感染后期肠道乳酸细菌数量和感染后期血清特异性IgG水平。

Effect of Dietary β-1,3-glucan Supplementation on Intestinal Redox,Microflora and Immune Functions of Broilers Challenged with Escherichia coli

Ninety one-day-old male broiler chicks (AA) were randomly divided into equal groups and placed in 3 isolation chambers respectively. The group 1 and 2 were fed a standard non-medicated diet,and the group 3 received the same diet supplemented with β-1,3-glucan. At d 8,9 and 10,each bird in the group 2 and 3 was challenged with 0.5 mL of serotype O78 strain of E.coil (1×1010 cfu/mL). Results indicated that the E.coil O78-challenged birds decreased BW (P<0.05),numerically increased mortality rate. Moreover,intestinal mocusa injury,increased jejunal and ileal sIgA contents (P<0.05),lower cecal lactobacilli population were also observed compared with the unchallenged birds fed an unmedicated diet. In contrast,dietary β-1,3-glucan supplementation could significantly prevent the reduction in BW (P<0.05) of birds,and decrease birds mortality numerically after challenge. Moreover,β-1,3-glucan could regulate the equilibrium of intestinal redoxes,induce serum specific IgG production and increase the number of cecal lactobacilli.